Tree-ring reconstructions of streamflow and their use in water management

Cheyenne, WY - September 6, 2007

This all-day workshop was organized at the request of Clint Bassett and Randy Hays, Cheyenne Board of Public Utilities (BOPU). They were interested in both a workshop similar to the previous ones held by Jeff Lukas and Connie Woodhouse, as well as the possibility of streamflow reconstructions for the three basins they draw water from.

For the morning session of the workshop, there were six participants from BOPU besides Bassett, five from the Wyoming Water Development Office (WWDO; a major funder of applied hydrologic research in Wyoming), and one each from several other state and local agencies (see participant list). Lukas gave a 90-minute presentation explaining how tree-rings record climate information, how tree-ring data are collected, processed, and used to generate streamflow reconstructions, and how water managers around the West are applying the reconstructions to water management. Steve Gray, Glenn Tootle, and Anthony Barnett of the University of Wyoming gave a 40-minute presentation describing the status of tree-ring work in several Wyoming basins, including new reconstructions for the upper Green and its tributaries, and the upper North Platte.

The afternoon session of the workshop included several BOPU staff, one WWDO staff member, Gray, Barnett, and Lukas. The focus of discussion was how to generate for BOPU tree-ring hydrologies relevant to their three gages of interest, which are in the Green, North Platte, and South Platte basins, respectively. The workshop was capped off by a short field session in the Vedauwoo area west of Cheyenne, where field techniques for collecting tree-ring data were demonstrated to the group.

The consensus of participants was that workshop was successful in conveying how tree-ring data are generated and used, in presenting the status of tree-ring data relevant to water management to Wyoming, and in laying the groundwork for the future use of tree-ring data by Wyoming's largest urban water provider, Cheyenne BOPU.

Jeff Lukas, University of Colorado & WWA